U.S. patent number 7,394,340 [Application Number 11/548,353] was granted by the patent office on 2008-07-01 for electromagnetic device, high-voltage generating device, and method for making the electromagnetic device.
This patent grant is currently assigned to Matsushita Electric Works, Ltd.. Invention is credited to Takaaki Chuzawa, Toru Fujiwara, Hidenori Kakehashi, Takashi Kanbara, Kazuhiko Kinutant, Takao Miyai, Tomoyuki Nakano, Masaki Satou, Kenichi Takamatsu.
United States Patent |
7,394,340 |
Kakehashi , et al. |
July 1, 2008 |
**Please see images for:
( Certificate of Correction ) ** |
Electromagnetic device, high-voltage generating device, and method
for making the electromagnetic device
Abstract
An electromagnetic device and a high-voltage generating device
which are thin and improved in the characteristics are provided in
which a magnetic core is made of a cylindrical form of a ferrite
material having a higher intrinsic resistance. A winding is
provided by winding a flat rectangular wire conductor in an
edge-wise winding form directly on substantially the entire length
of the magnetic core. As any insulator such as a coil bobbin is not
needed between the flat rectangular wire conductor and the magnetic
core, the winding can be decreased in the overall size or thickness
thus contributing to the dimensional reduction of the
electromagnetic device. Also, as its flat rectangular wire
conductor is wound directly on the magnetic core, the winding can
be minimized in the length and thus the overall resistance.
Moreover, as there is no gap between the winding and the magnetic
core, the self-inductance can be reduced while the size and the
number of turns of the winding remain unchanged.
Inventors: |
Kakehashi; Hidenori (Takatsuki,
JP), Kanbara; Takashi (Moriguchi, JP),
Fujiwara; Toru (Akashi, JP), Takamatsu; Kenichi
(Niigata, JP), Nakano; Tomoyuki (Sakai,
JP), Kinutant; Kazuhiko (Niigata, JP),
Chuzawa; Takaaki (Hirakata, JP), Satou; Masaki
(Niigata, JP), Miyai; Takao (Hirakata,
JP) |
Assignee: |
Matsushita Electric Works, Ltd.
(Osaka, JP)
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Family
ID: |
26600049 |
Appl.
No.: |
11/548,353 |
Filed: |
October 11, 2006 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20070132535 A1 |
Jun 14, 2007 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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10129105 |
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7142082 |
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PCT/JP01/08022 |
Sep 14, 2001 |
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Foreign Application Priority Data
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Sep 14, 2000 [JP] |
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2000-280666 |
Jan 19, 2001 [JP] |
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2001-012224 |
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Current U.S.
Class: |
336/180; 29/605;
336/181; 336/182 |
Current CPC
Class: |
C12N
15/101 (20130101); C12Q 1/6827 (20130101); H01F
17/045 (20130101); H01F 30/06 (20130101); H01F
38/10 (20130101); H01F 41/082 (20160101); H05B
41/042 (20130101); C12Q 1/6827 (20130101); H01F
27/2823 (20130101); H01F 2017/046 (20130101); Y10T
29/49071 (20150115); C12Q 2565/137 (20130101); C12Q
2527/107 (20130101) |
Current International
Class: |
H01F
27/28 (20060101); H01F 27/34 (20060101) |
Field of
Search: |
;336/180-182 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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85104717 |
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Dec 1986 |
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CN |
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1040970 |
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Oct 2000 |
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EP |
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60-119708 |
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Aug 1985 |
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JP |
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02198113 |
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Aug 1990 |
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JP |
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2-222509 |
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Sep 1990 |
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JP |
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5-109554 |
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Apr 1993 |
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JP |
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11-016752 |
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Jan 1999 |
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JP |
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11-074132 |
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Mar 1999 |
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JP |
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11-114674 |
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Apr 1999 |
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JP |
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11-297547 |
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Oct 1999 |
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JP |
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2000-036416 |
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Feb 2000 |
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JP |
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2000-040629 |
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Feb 2000 |
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JP |
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2000-124040 |
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Apr 2000 |
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JP |
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2000-150266 |
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May 2000 |
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JP |
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2000-173840 |
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Jun 2000 |
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JP |
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Other References
English Language Abstract of JP 11-016752. cited by other .
English Language Abstract of JP 11-074132. cited by other .
English Language Abstract of JP 11-114674. cited by other .
English Language Abstract of JP 2000-036416. cited by other .
English Language Abstract of JP 2000-150266. cited by other .
English Language Abstract of JP 2000-124040. cited by other .
English Language Abstract of JP 60-119708. cited by other .
English Language Abstract of JP 5-109554. cited by other .
English Language Abstract of JP 2000-040629. cited by other .
English Language Abstract of JP 2000-173840. cited by other .
English Language Abstract of JP 2-222509. cited by other .
English Language Abstract of JP 11-297547. cited by other .
English Language Abstract of CN 85104717. cited by other.
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Primary Examiner: Mai; Anh T
Attorney, Agent or Firm: Greenblum & Bernstein,
P.L.C.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of pending U.S. patent
application Ser. No. 10/129,105, filed Jun. 7, 2002, which is a
U.S. National Stage Application of PCT/JP01/08022, filed on Sep.
14, 2001, the disclosures of which are expressly incorporated
herein by reference in their entirety.
Claims
What is claimed is:
1. An electromagnetic device comprising: a magnetic core having a
curved side and a flat rectangular wire conductor being wound in an
edge-wise winding form directly contacting the curved side of the
magnetic core, wherein the magnetic core has a bottomed hole
provided in each end thereof and the hole being tapered.
2. An electromagnetic device according to claim 1, wherein the
magnetic core has an elliptical shape in a cross section.
3. A method for making an electromagnetic device comprising a
magnetic core having a curved side and a flat rectangular wire
conductor being wound in an edge-wise winding form directly
contacting the curved side of the magnetic core, the method
comprising: winding the flat rectangular wire conductor in the
edge-wise winding form directly contacting the magnetic core; and
fixedly joining ends of the flat rectangular wire conductor
provided in the edge-wise winding form to corresponding terminals
which are provided integrally on a single metal strip, wherein as
the ends of the flat rectangular wire conductor have been fixedly
joined to the corresponding terminals of the metal strip, a
redundancy of the metal strip is separated from the terminals to
electrically isolate the ends of the flat rectangular wire
conductor from the metal strip.
4. The method for making an electromagnetic device according to
claim 3, wherein the magnetic core has an elliptical shape in a
cross section.
Description
FIELD OF THE INVENTION
The present invention relates to an electromagnetic device, a
high-voltage generating device, and a method for making the
electromagnetic device.
BACKGROUND OF THE INVENTION
It is necessary for starting a high intensity discharge lamp such
as a high-intensity discharge (HID) lamp to use a high-voltage
generating device called an igniter. The high-voltage generating
device is generally provided in the form of an electromagnetic
device such as a pulse transformer for converting a low-voltage
input to a high-voltage output of pulsed waveform (as disclosed in,
for example Japanese Patent Laid-open Publications 11-16752 and
11-74132).
One of such conventional electromagnetic devices is shown in
structure in FIGS. 65 to 68. A coil bobbin 60 is made of an
insulating material such as synthetic resin having substantially a
cylindrical shape which comprises two outer flanges 61 at both ends
and a partition flange 62 between the two outer flanges 61. A
primary winding 63 at the low voltage side is wound between one of
the two outer flanges 61 and the partition flange 62 while a
secondary winding 64 at the high voltage side is wound between the
other outer flange 61 and the partition flange 62. In particular,
the secondary winding 64 is fabricated by winding a long, flat
rectangular foil conductor with its wider sides facing each other
(in the form of, so-called, edge-wise winding) for improving both
the edge side insulation and the contact area of windings. Finally,
a couple of U-shaped magnetic cores 65 made of Mn--Zn ferrite are
inserted and joined to both ends of the coil bobbin 60 with the
primary winding 63 and the secondary winding 64, hence forming an
electromagnetic device (a pulse transformer).
FIG. 69a is a perspective view of another conventional
electromagnetic device and FIG. 69b is a cross sectional view taken
along the line A-A' of FIG. 69a. The another conventional
electromagnetic device comprises a bar-like magnetic core 3PA and a
coil winding 2 wound as the secondary winding on a coil bobbin 60
thereof mounted on the magnetic core 3PA. For ease of winding the
coil winding 2 on the coil bobbin 60 secured to the magnetic core
3PA, a recess 31PA is provided in each end of the magnetic core 3PA
to determine its position along the axial direction. A process of
fabricating the bar-like magnetic core 3PA having the recess in
each end thereof will be explained referring to FIG. 70. The
process of fabricating the magnetic core 3PA employs a pair of rods
K, each having a projection K1' for shaping the recess 31PA and a
swage die U having a through hole U1 provided therein for insertion
of the rods K. As shown in FIG. 70a, the process starts with
shaping the magnetic core 3PA using the die U and the rods K. Then,
the lower rod K is lifted up to the upper end of the die U as shown
in FIG. 70b to remove the magnetic core 3PA from the die U in the
direction denoted by the arrow for increasing the efficiency. The
magnetic core 3PA may however be injured at the edge R1 of the
recess 31PA upon being removed from the die U as shown in FIG.
71.
FIG. 72 is a perspective view of a further conventional
electromagnetic device. The electromagnetic device shown is a pulse
transformer for converting a low voltage input to a high voltage
output as called an igniter to generate a high voltage for
energizing a high intensity discharge lamp. The conventional device
shown in FIG. 72 comprises a bar-like magnetic core 3PA, a bobbin
4PA, a pair of coil windings 9 and 10 mounted on the bobbin 4PA
mounted to the magnetic core 3PA, a casing 5PA made of a resin
material for enclosing those components therein, and terminals 6
connected to coil windings 9 and 10 at one end and extending at the
other end from the casing 5PA. The coil winding 9 incorporates an
insulation coated wire (of round wire) comprising an electrical
conductor having a round shape in the cross section and an
insulating coating provided over the wire conductor and serving as
the primary winding while the coil winding 10 serves as the
secondary winding. The coil winding 9 is connected to one (61) of
the terminals 6 and the coil winding 10 is connected to another
(62).
This conventional electromagnetic device is fabricated by winding
the coil windings 9 and 10 on the bobbin 4PA, inserting the
magnetic core 3PA into the bobbin 4PA, assembling those in the
casing 5PA, connecting the terminals 6 to the corresponding coil
windings 9 and 10, and filling the casing 5PA with an amount of
epoxy resin (by vacuum filling process).
FIG. 73 is a perspective view of a conventional welding joiner
welded to the insulation coated wire. A welding joiner 6PA which
can be welded to the insulation coated wire without stripping the
insulation coating comprises, as shown in FIG. 73, a flat base
portion 61 extending along one direction and a folded portion 62
extending from one side of the base portion 61 at a right angle to
the direction and folded along its width at a portion 63 so that
the two portions 61 and 62 confront each other. The welding joiner
6PA is preferably utilized as the terminal 6 of the conventional
electromagnetic device. One example of this arrangement is
disclosed in Japanese Patent Laid-open Publication 11-114674.
It is common that high intensity discharge lamps are widely used as
the head lights of vehicles because they are high in the
brightness, low in the power consumption, and long in the operating
life and thus much favorable in the safety than any halogen lamps.
As such high intensity discharge lamps have increasingly been
popular, the electromagnetic devices are now desired for minimizing
the thickness in view of the dimensional requirements of igniters.
However, the conventional devices are hardly reduced in the
thickness with the coil bobbin 60 provided between the magnetic
core 65 (See FIG. 65) and the coil. Also, there is essentially
provided a gap between the coil bobbin 60 and the magnetic core 65
for ease of mounting, thus elongating the distance between the
magnetic core 65 and the coil and creating differences in the
properties between the electromagnetic devices. Although a
modification is proposed where the coil bobbin is replaced by an
insulating cover made of a resin material (disclosed in Japanese
Patent Laid-open Publication 2000-36416), it retains the same
drawbacks.
When the bobbin is provided between the magnetic core and the coil
windings, its terminals are fixedly connected to the coil windings.
In case of a bobbin-less device, the terminals connected with the
coil windings may be secured with much difficulty.
The process of fabricating an electromagnetic device shown in FIG.
72 requires substantially four or more hours for carrying out the
major processing steps including preparation, drying, and curing
steps. For implementing a scheme of mass production, extra
investments for expanding the existing production facility has to
be needed. Also, when the epoxy resin vacuum filling process is
employed, it may limit the lead-out of the terminals 6 from the
casing 5PA to one single direction. This prevents the terminals 6
from being respectively bent and oriented in a desired pattern of
the circuitry planning. Since the coil windings of a metallic
material create undesired events of spring back, their ends have to
be bound together or supported by any proper means. The epoxy resin
vacuum filling process may generally develop an interface between
the casing 5PA and the epoxy resin material thus allowing a high
voltage to leak from the interface. The edge-wise winding may cause
the coating of the coil windings to be peeled off when its
curvature radius is too small.
The convention welding joiner 6PA may often cause the insulation
coated wire to be dislocated when held between the base portion 61
and the folded portion 62 and pressed with a pair of welding
electrodes. If worse, the insulation coated wire may completely be
slipped off from between the base portion 61 and the folded portion
62. As the welding of the insulation coated wire to the welding
joiner is carried out only with poor consistency, it is much
desired to modify the welding joiner for improvement of its stable
joining function and operational reliability.
The present invention has been developed in view of the foregoing
aspects and its object is to provide an electromagnetic device, a
high-voltage generating apparatus, and a method for making the
electromagnetic device where the dimensional reduction and the
improvement of properties are achieved, and the duration of time
required for carrying out the production steps is minimized.
DISCLOSURE OF THE INVENTION
In the present invention, an electromagnetic device comprises a
magnetic core having a curved side and a flat rectangular wire
conductor wound in an edge-wise winding form directly on the curved
side of the magnetic core. Accordingly, as any insulator such as a
coil bobbin is not needed between the flat rectangular wire
conductor and the magnetic core, the winding can be decreased in
the overall size or thickness, thus contributing to the dimensional
reduction and the improvement of characteristics of the device. In
the device, the magnetic core has an intrinsic resistance of not
smaller than 1000 .OMEGA.m.
The electromagnetic device further comprises a winding provided on
the outer surface of the flat rectangular wire conductor.
Accordingly, a resultant transformer can be reduced in the
thickness.
The magnetic core is rough finished at the surface. Accordingly, as
no extra step such as polishing is needed after the completion of
the magnetic core, the production cost of the magnetic core can be
lowered. Also, the flat rectangular wire conductor can be protected
from slipping and tilting down during the edge-wise winding
process.
The flat rectangular wire conductor and the winding are joined to
each other by fusing their coatings. Accordingly, as the
positioning between the windings is securely determined, variations
in the properties resulting from relative dislocation between the
windings will be avoided.
The magnetic core of an edge-wise winding form of the flat
rectangular wire conductor is located between a group of leads
joined together. Accordingly, the winding is arranged with its
leads extending over the outer surface of the flat rectangular wire
conductor.
The electromagnetic device further comprises a first insulating
member arranged of a cylindrical shape to which the magnetic core
of the flat rectangular wire conductor is fitted and a secondary
insulating material covering over the first insulating member and
the winding which is made of an electrically conductive resin
material and provided on the outer side of the first insulating
member. Accordingly, the insulation between the winding of the flat
rectangular wire conductor and the winding of the electrically
conductive resin material can be ensured by the first insulating
material.
The first insulating member has a groove provided in the outer side
thereof and the winding is fabricated by filling the groove with an
electrically conductive resin material. Accordingly, the insulation
between the high-voltage end of the winding of the flat rectangular
wire conductor and the winding of the electrically conductive resin
material can be ensured. The flat rectangular wire conductor serves
as a secondary winding and the winding serves as a primary
winding.
The primary winding is located adjacent to the low-voltage end of
the secondary winding. Accordingly, the surface distance between
the high-voltage side of the secondary winding and the primary
winding can be increased thus improving the insulating
function.
One of two ends of the primary winding disposed at the high-voltage
end side of the secondary winding is drawn to the low-voltage end
of the secondary winding. Accordingly, the insulation can be
improved to a desired level.
The primary winding is an insulated wire or a magnet wire protected
with an insulation coating for electrically insulating between the
primary winding and the secondary winding. Accordingly, the
insulation can be improved to a desired level.
The magnetic core has an elliptical shape in the cross section and
its flat rectangular wire conductor is drawn out at both ends
through a space between a transformer consisting mainly of the
magnetic core and the flat rectangular wire conductor and a
rectangular housing mounted outwardly of the transformer.
Accordingly, the transformer can be reduced in both the size and
the cost.
The magnetic core has a bottomed hole provided in each end thereof
and the hole is arranged of a tapered shape which becomes gradually
smaller in the diameter from the opening to the bottom.
Accordingly, when the magnetic core is fallen down about the point
at the edge of its bottom with its bottomed hole accepting the
projection of the rod during the preparation of the magnetic core
using the paired rods and a pair of punching dies, its portion
about the bottomed hole can clear the projection of the rod. As a
result, the magnetic core can be protected from being tipped off at
its edge about the bottomed hole of its bottom.
The magnetic core has an elliptical shape in the cross section.
Accordingly, the overall size can be thinned.
In the present invention, an electromagnetic device having a
transformer arrangement includes a bar-like magnetic core and a
flat rectangular wire conductor wound on the outer surface of the
magnetic core for generation of a high voltage, the flat
rectangular wire conductor drawn out at both ends from two ends of
the magnetic core respectively, characterized by a resin outer
housing provided about the transformer by filling or molding an
insulating resin material and having at least one side thereof
configured up and down along a direction substantially parallel
with the axial direction of the magnetic core. Accordingly, as the
surface distance is increased by the effect of the up and down
configuration, the insulation function can be improved.
The up and down configuration is provided at the high-voltage end
side of the flat rectangular wire conductor. Accordingly, the
insulation function can be improved.
In the present invention, an electromagnetic device having a
transformer arrangement includes a magnetic core, a winding and a
flat rectangular wire conductor both provided on the magnetic core,
and at least two terminals for connection of the winding and the
flat rectangular wire conductor with the outside, characterized in
that the transformer is sealed in an injection molded form of a
thermoset resin material. Accordingly, the production of the
transformer can be simplified.
The electromagnetic device further comprises a lead frame for
supporting the components during the injection molding.
Accordingly, the production can be simplified.
The thermoset resin material is covered with a molded form of a
thermoplastic resin material. Accordingly, the insulation can be
ensured while the protection against moisture is effectively
improved.
The winding and the flat rectangular wire conductor are secured at
least at one end with an adhesive. Accordingly, the coil winding
can hardly be loosened by the effect of spring back.
While the winding acts as a primary winding, the flat rectangular
wire conductor acts as a secondary winding and is insulated by
coating and provided in an edge-wise winding form on the magnetic
core. Accordingly, the overall size can be minimized.
In the present invention, an insulation coated wire is joined with
a welding joiner which comprises a flat base portion extending in
one direction and a folded portion extending from one side along
the one direction of the base portion substantially at a right
angle to the one direction, where the folded portion is folded down
along the one side to face the base portion, and the base portion
has a tab portion extending from the other side than the one side
thereof and bent upright to form a positional error inhibitor.
Accordingly, when the welding joiner is pressed by welding
electrodes for joining, the insulation coated wire can securely be
held with but not detached from the welding joiner and its joining
can hence be maintained and improved in both the stability and the
durability.
The length of the tab positional error inhibiting portion from the
base portion is equal to or slightly greater than the diameter of
the insulation coated wire. Accordingly, as the insulation coated
wire when dislocated is securely held by the positional error
inhibitor of the welding joiner, it can definitely remain protected
from being detached from the welding joiner.
The positional error inhibiting portion is distanced from the
folded portion. Accordingly, as any short-circuit between the
positional error inhibiting portion and the folded portion is
avoided, Joule heat generated by energization can successfully be
radiated from the extending side of the folded portion of the
joiner.
In the present invention, a high-voltage generating device
comprises: a pulse transformer having a magnetic core, a flat
rectangular wire conductor wound in an edge-wise winding form
directly on the outer surface of the magnetic core, and a winding
provided on the outer side of the flat rectangular wire conductor;
a capacitor connected in parallel with the primary winding of the
pulse transformer; a switching element for opening and closing the
discharging path extending from the capacitor to the primary
winding; and a resistor connected to the primary winding.
Accordingly, as any insulator such as a coil bobbin is not needed
between the magnetic core and the winding (of the flat rectangular
wire conductor), the winding can be decreased in the overall size
or thickness thus implementing a thin, property improved
high-voltage generating device. Also, as its undesired oscillation
is attenuated by resistance loss in the resistor connected in
parallel with the primary winding, the pulsed high-voltage output
of the secondary winding of the pulse transformer can favorably be
corrected to substantially a fundamental waveform. Moreover, since
the oscillation of the voltage is readily settled down, any
unwanted stress on the components including the capacitor can
successfully be eased. As a result, the components to be used may
be declined in the resistance to high voltage and reduced in the
size and the cost.
In the present invention, a high-voltage generating device
comprises: a pulse transformer having a magnetic core, a flat
rectangular wire conductor wound in an edge-wise winding form
directly on the outer surface of the magnetic core, and a winding
provided on the outer side of the flat rectangular wire conductor;
a capacitor connected in parallel with the primary winding of the
pulse transformer; a switching element for opening and closing the
discharging path extending from the capacitor to the primary
winding; and metal strips provided adjacent to at least one end of
the pulse transformer in an open magnetic circuit. Accordingly, as
any insulator such as a coil bobbin is not needed between the
magnetic core and the winding (of the flat rectangular wire
conductor), the winding can be decreased in the overall size or
thickness thus implementing a thin, property improved high-voltage
generating device.
The pulse transformer, the capacitor, and the switching element are
installed in a housing which has a socket for connecting the base
of a discharge lamp electrically and mechanically, whereby the base
of the discharge lamp is supplied with a pulsed high voltage
generated at the secondary winding of the pulse transformer.
Accordingly, a thin, property improved high-voltage generating
device can be realized having the socket for connection to the base
of a discharge lamp.
In the present invention, a method for making an electromagnetic
device comprises the steps of: winding a flat rectangular wire
conductor in an edge-wise winding form on a magnetic core; and
fixedly joining ends of the flat rectangular wire conductor
provided in the edge-wise winding form to corresponding terminals
which are provided integrally on a single metal strip. Accordingly,
the duration required for the production can be decreased. Also,
with no use of insulators, the ends of the coil winding can be
joined to the corresponding terminals.
In the above method, the metal strip is arranged of a linear form
to which the ends of the flat rectangular wire conductor are joined
as drawn out in one direction towards the metal strip. Accordingly,
the metal strip can be arranged of a simple shape.
In the method, as the ends of the flat rectangular wire conductor
have fixedly been joined to the corresponding terminals of the
metal strip, the redundancy of the metal strip is separated from
the terminals for electrically isolating the ends of the flat
rectangular wire conductor from the metal strip. Accordingly, the
electromagnetic device with its coil winding joined at the ends to
the corresponding terminals with no use of insulators can be
fabricated by using simpler steps.
In the method, the magnetic core has an elliptical shape in the
cross section. Accordingly, the downsizing and the cost down can be
feasible.
In the present invention, a method for making an electromagnetic
device with the use of a winding jig for holding one end of a
magnetic core, a center shaft for supporting the center axis of the
magnetic core, a hold-down jig arranged slidable on the magnetic
core and the center shaft, a hold-down spring urging a stress
against the hold-down jig, and a spring holder arranged slidable in
response to the width of winding, comprises the steps of: coupling
one end of a flat rectangular wire conductor to the winding jig
joined to the magnetic core and rotating the winding jig; winding
the flat rectangular wire conductor on the magnetic core which is
rotated by the rotating action of the winding jig; and allowing the
hold-down jig and the spring holder to be slid to protect the flat
rectangular wire conductor from tilting down as the width of
winding increases during the edge-wise winding of the flat
rectangular wire conductor on the magnetic core between the winding
jig and the hold-down jig.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view showing Embodiment 1 of the present
invention;
FIG. 2 is a cross sectional view of the same;
FIG. 3 is a perspective view showing Embodiment 2 of the present
invention;
FIG. 4 is an explanatory view illustrating a process of fabricating
the same;
FIG. 5 is a perspective view showing Embodiment 3 of the present
invention;
FIG. 6 is a cross sectional view of the same in use;
FIG. 7 is a cross sectional view of a magnetic core in Embodiment
4;
FIG. 8 is a perspective view of the magnetic core on which a flat
rectangular wire conductor is being wound;
FIG. 9 is a perspective of the same;
FIG. 10 is a perspective view showing Embodiment 5 of the present
invention;
FIG. 11 is a cross sectional view of the same;
FIG. 12 is a perspective view showing Embodiment 6 of the present
invention;
FIG. 13 is a cross sectional view of a magnetic core in Embodiment
7;
FIG. 14 is a perspective view of the same;
FIG. 15 is a perspective view showing Embodiment 8 of the present
invention;
FIG. 16 is a cross sectional view of the same;
FIG. 17 is a perspective view showing Embodiment 9 of the present
invention;
FIG. 18 is a cross sectional view of the same;
FIG. 19 illustrates a magnetic core in the embodiment where FIG.
19a is a front view and FIG. 19b is a side view of the same;
FIG. 20 is a cross sectional view of a modification;
FIG. 21 is a perspective view showing Embodiment 10 of the present
invention;
FIG. 22 is a cross sectional view of the same;
FIG. 23 is a perspective view showing Embodiment 11 of the present
invention;
FIG. 24 is a cross sectional view of the same;
FIG. 25 is an explanatory view illustrating a process of
fabricating the same;
FIG. 26 is a perspective view showing Embodiment 12 of the present
invention;
FIG. 27 is a cross sectional view of the same;
FIG. 28 is a perspective view showing Embodiment 13 of the present
invention;
FIG. 29 is a partially omitted perspective view showing Embodiment
14 of the present invention;
FIG. 30 is a perspective view showing Embodiment 15 of the present
invention;
FIG. 31 is a cross sectional view of the same;
FIG. 32 is a perspective view of a cylindrical body in the
same;
FIG. 33 is an explanatory view showing a process of fabricating the
same;
FIG. 34 is a perspective view of a primary winding in the same;
FIG. 35 is an explanatory view of the same;
FIG. 36 is a plan view showing Embodiment 16 of the present
invention;
FIG. 37 is a waveform diagram illustrating an action of the
same;
FIG. 38 is a schematic circuitry diagram showing a conventional
high-voltage generating device;
FIG. 39 is a waveform diagram showing an action of the conventional
device;
FIG. 40 is a schematic circuitry diagram showing Embodiment 17 of
the present invention;
FIG. 41 is a schematic circuitry diagram of a modification of the
same;
FIG. 42 is a perspective view showing Embodiment 18 of the present
invention;
FIG. 43 is an exploded perspective view of the same;
FIG. 44 is a perspective view seen from the back of a body of the
same;
FIG. 45 is a side view of a pulse transformer in the same;
FIG. 46 is a schematic view of an electromagnetic device showing
Embodiment 19 of the present invention;
FIG. 47 is an explanatory view of the shape of recess provided in
each end of a magnetic core showing Embodiment 20 of the present
invention;
FIG. 48 is a view of a magnetic core in an electromagnetic device
showing Embodiment 21 of the present invention;
FIG. 49 is a view of a magnetic core and coil windings in an
electromagnetic device showing Embodiment 22 of the present
invention;
FIG. 50 is a view of a magnetic core, coil windings, and an
insertion molded member in an electromagnetic device showing
Embodiment 23 of the present invention;
FIG. 51 is a view of a magnetic core, coil windings, and an
insertion molded member in an electromagnetic device showing
Embodiment 24 of the present invention;
FIG. 52 is a schematic view of an electromagnetic device during its
production showing Embodiment 25 of the present invention;
FIG. 53 is a plan view of the electromagnetic device shown in FIG.
52:
FIG. 54 is a view of a magnetic core and coil windings used for
fabricating the electromagnetic device shown in FIG. 52;
FIG. 55 is a schematic view of the electromagnetic device prior to
that shown in FIG. 52;
FIG. 56 is a plan view of the electromagnetic device shown in FIG.
55;
FIG. 57 illustrates a perspective view and a partial cross
sectional view of an electromagnetic device showing Embodiment 26
of the present invention;
FIG. 58 is a plan view of the electromagnetic device shown in FIG.
57;
FIG. 59 is an explanatory view showing a process of fabricating the
electromagnetic device shown in FIG. 58 from its previous form;
FIG. 60 is a view showing a discharge lamp igniter employing the
electromagnetic device;
FIG. 61 is a view showing an igniter circuit provided in the
discharge lamp igniter shown in FIG. 60;
FIG. 62 is a view of a magnetic core and coil windings in an
electromagnetic device showing Embodiment 27 of the present
invention;
FIG. 63 is a view of a magnetic core and coil windings in an
electromagnetic device showing Embodiment 28 of the present
invention;
FIG. 64 is a view of a welding joiner showing Embodiment 29 of the
present invention;
FIG. 65 is an exploded perspective view of a prior art;
FIG. 66 is a perspective view of the same;
FIG. 67 is a cross sectional view of the same;
FIG. 68 is a perspective view of a coil bobbin in the same;
FIG. 69 illustrates a perspective view and a cross sectional view
of a conventional electromagnetic device;
FIG. 70 is an explanatory view showing a process of fabricating a
bar-like magnetic core having a bottomed hole provided in each end
thereof;
FIG. 71 is an explanatory view of the magnetic core shown in FIG.
69;
FIG. 72 is a perspective view of another conventional
electromagnetic device; and FIG. 73 is a perspective view of a
conventional welding joiner welded to an insulation coated
wire.
BEST MODES FOR EMBODYING THE INVENTION
Embodiment 1
An electromagnetic device of this embodiment is a single-winding
inductor having a winding wound directly on a rod magnetic core 3
arranged of substantially a cylindrical shape with no need of an
insulator such as a coil bobbin as shown in FIGS. 1 and 2.
The magnetic core 3 is made of an Ni--Zn ferrite material which is
high in the resistivity (intrinsic resistance) and about 8 mm in
the diameter of its cylindrical shape. The winding is a flat
rectangular wire conductor 2 (for example, having a thickness of 70
.mu.m and a width of 1.4 mm) wound in a single layer of edge-wise
winding form on substantially the entire length of the magnetic
core 3. More specifically, the flat rectangular wire conductor 2 is
wound on the magnetic core 3 which is secured at both axial ends to
jigs and then rotated by a rotating motion of the jigs.
It is found from examination of the insulation coating (not show)
of the flat rectangular wire conductor 2 wound on the magnetic core
3 in the inductor of this embodiment that the insulation between
the winding (of the flat rectangular wire conductor 2) and the
magnetic core 3 and between any two adjacent turns of the winding
is highly ensured. Although the insulation between the winding and
the magnetic core 3 depends on the resistivity which is one of the
insulating properties of the magnetic core 31 it remains explicitly
favorable when the resistivity is not smaller than 1000 .OMEGA.m.
It is also found that the magnetic and electric properties remain
not declined.
As its flat rectangular wire conductor 2 is directly wound in an
edge-wise winding form on the magnetic core 3 made of a
high-resistivity material, the inductor eliminates the use of any
insulator such as the coil bobbin 60 between the winding (of the
flat rectangular wire conductor 2) and the magnetic core 3 and can
thus be minimized in the thickness with its winding reduced in the
external dimensions. Also, as the flat rectangular wire conductor 2
is directly wound on the magnetic core 3, its winding can be
shortened in the overall length thus declining the level of
resistance. Moreover, as the inductor develops no gap between the
winding and the magnetic core 3, its self-inductance can
comparatively be decreased with the dimensions and the number of
windings remaining unchanged. The conventional electromagnetic
device having the flat rectangular wire conductor wound in an
edge-wise winding form on an insulator such as the coil bobbin
develops a gap between the winding and the magnetic core which then
makes the relative positional relationship between the winding and
the magnetic core unstable, hence creating variations in the
properties including the inductance. Because the flat rectangular
wire conductor 2 is directly wound on the magnetic core 3 in the
embodiment, they are closely secured to each other and their
relative position can be secured thus minimizing variations in the
properties.
Embodiment 2
This embodiment is characterized by a magnetic core 3 having an
elliptical shape in the cross section as shown in FIG. 3. As the
other arrangement is identical to that of Embodiment 1, like
components are denoted by like numerals and will be described in no
more detail (throughout the embodiments and their drawings).
The magnetic core 3 is made of an Ni--Zn ferrite material identical
to that of Embodiment 1 but having an elliptical shape in the cross
section on which a flat rectangular wire conductor 2 is directly
wound in an edge-wise winding form. As its magnetic core 3 has an
elliptical shape in the cross section, the inductor can be lower in
the height than that of Embodiment 1.
The magnetic core 3 has a hemispheric recess (pit) 3c of about 2 mm
in diameter provided at the center in each end thereof. While the
flat rectangular wire conductor 2 is being wound on the magnetic
core 3 by the action of a winder 4, the magnetic core 3 is secured
to the winder with its recess 3c tightly accepting the
corresponding projection of a jig of the winder.
This will be explained in more detail referring to FIGS. 4a to 4f.
The winder 4 has a magnetic core holding jig 4b mounted on a rotary
shaft 4a thereof, as shown in FIG. 4a. The magnetic core 3 is then
inserted into the center recess of the magnetic core holding jig 4b
and held at its hemispheric recess 3c engaged with the tip of a
center shaft 4c of the winder 4. A hold-down jig 4d is also
provided for rotating and sliding motion on and along the center
shaft 4c. The hold-down jig 4d remains urged by a hold-down spring
4e so as to hold the flat rectangular wire conductor 2 in the
vertical position during the edge-wise winding action.
Additionally, a slidable spring support 4f is provided for loading
the flat rectangular wire conductor 2 with substantially a uniform
pressure. As a result, the magnetic core 3 is uniformly held along
its axis of rotation and its rotation can be stable with minimum of
the rotation error derived from its dimensional variations thus
ensuring a stability of the winding action.
Then, with the magnetic core 3 being held by the jigs as shown in
FIG. 4b, the flat rectangular wire conductor 2 is joined at the end
to a conductor retainer 4g on the magnetic core holding jig 4b as
shown in FIG. 4c. As the rotary shaft 4a of the winder 4 starts
rotating together with the magnetic core holding jig 4b, the
magnetic core 3, the hold-down jig 4d, and the center shaft 4c, the
flat rectangular wire conductor 2 is directly wound on the magnetic
core 3. As the winding proceeds, an edge-wise winding form of the
flat rectangular wire conductor 2 is produced between the magnetic
core holding jig 4b and the hold-down jig 4d and its width
increases. As the width increases, the hold-down jig 4d and the
spring support 4f are shifted together with the yielding length of
the hold-down spring 4e kept uniform. This allows the flat
rectangular wire conductor 2 to remain at its vertical position,
hence ensuring a stability of the winding action. FIG. 4f
illustrates the hold-down jig 4d and the spring support 4f shifted
to the right by a width of the winding.
As described, the inductor having the flat rectangular wire
conductor 2 wound directly on the magnetic core 3 of the elliptical
shape in the cross section, like that of Embodiment 1, can be
minimized in the size, particularly the height and in the
inductance variation.
While the flat rectangular wire conductor is directly wound on the
core according to Embodiment 1, the core may be covered with a
coating for increasing the level of insulation or protected at the
sides (where the flat rectangular wire conductor is wound) with a
tape of insulating material. This also allows the flat rectangular
wire conductor to be wound by the rotating action of the magnetic
core, thus contributing to the small size of the inductor.
Embodiment 3
This embodiment is characterized by a magnetic core 3 having a
through hole 3d provided along the axial direction therein as shown
in FIG. 5. The magnetic core 3 like that of Embodiment 2 is
arranged of an elliptical shape in the cross section and its
through hole 3d of about 2 mm in the diameter extends along the
axial direction between two ends thereof. This allows the magnetic
core 3 to be securely held by a jig inserting into the through hole
3d for ease of the winding of the flat rectangular wire conductor
2. In addition, the magnetic core 3 can tightly be secured to a
housing 7 of the winder with its through hole 3d accepting and
engaging with a bar-like projection 7a extending from the housing
7, as shown in FIG. 6. The projection 7a may be implemented by a
retaining screw. The magnetic core 3 may be arranged of a
cylindrical shape similar to that of Embodiment 1.
Embodiment 4
This embodiment is characterized by a magnetic core 3 having a pair
of outer flanges 8 provided on both ends thereof to extend
outwardly, as shown in FIGS. 7 to 9. The magnetic core 3 like that
of Embodiment 2 has an elliptical shape in the cross section and
its outer flanges 8 project from the lengthwise ends radially
(outwardly) at substantially a right angle to the lengthwise
direction. When wound in an edge-wise winding form, a flat
rectangular wire conductor 2 may be loosened out at both ends of
the magnetic core 3. This is inhibited by the outer flanges 8 which
holds the flat rectangular wire conductor 2 at the two ends.
Also, a plurality (two in this embodiment) of hemispheric recesses
3c are provided in each end of the magnetic core 3. During the
winding of the flat rectangular wire conductor 2, the magnetic core
3 is tightly secured to the winder with its recesses 3c accepting
and engaging with corresponding projections of a winder 4 which can
rotate. This allows the winding of the flat rectangular wire
conductor 2 to be more stable than in Embodiment 2. The magnetic
core 3 may be arranged of a cylindrical shape similar to that of
Embodiment 1.
Embodiment 5
This embodiment is characterized by a magnetic core 3 having a
particular shape shown in FIGS. 10 and 11. The shape of the
magnetic core 3 on which a flat rectangular wire conductor 2 is
directly wound in an edge-wise winding form becomes smaller in the
diameter of the cross section from both lengthwise ends to the
center. Accordingly, the outer surface of the magnetic core 3 is
sloped down from the two ends to the center and allows the flat
rectangular wire conductor 2 to be closely wound without loosening
towards the lengthwise ends of the magnetic core 3, thus ensuring a
stability of the winding form. The magnetic core 3 may be arranged
of an elliptical shape in the cross section similar to that of
Embodiment 2.
Embodiment 6
An electromagnetic device of this embodiment is a two-winding
transformer having a primary winding and a secondary winding wound
directly on a substantially cylindrical, rod-like magnetic core 3
thereof, shown in FIG. 12, with no use of an insulator such as a
coil bobbin.
The magnetic core 3 is substantially identical in the construction
to that of Embodiment 1 where flat rectangular wire conductors 2
are wound in an edge-wise winding form on the magnetic core 3 to
implement the primary winding 9 and the secondary winding 10. As
its primary winding 9 and secondary winding 10 are implemented by
the edge-wise winding of the flat rectangular wire conductors 2
directly on the magnetic core 3, the transformer can be decreased
in the overall size as compared with the conventional arrangement
having the windings wound on the coil bobbin and declined in the
direct-current resistance of both the primary winding 9 and the
secondary winding 10, hence improving its properties. Also, as the
primary winding 9 and the secondary winding 10 are separated from
each other along the lengthwise direction of the magnetic core 3,
the insulation between them can highly be ensured. The magnetic
core 3 may be arranged of an elliptical shape in the cross section
similar to that of Embodiment 2.
Embodiment 7
This embodiment is characterized by a magnetic core 3 having a
particular shape shown in FIGS. 13 and 14. The magnetic core 3 has
a pair of outer flanges 8a and 8b provided on both lengthwise ends
thereof to extend radially (outwardly) from their edge at
substantially a right angle to the lengthwise direction and a
partition flange 11 provided at a region biased from the center to
one end thereof to extend radially (outwardly) at substantially a
right angle to the lengthwise direction. This allows a flat
rectangular wire conductor 2 to be directly wound in an edge-wise
winding form between the outer flange 8a and the partition flange
11 on the magnetic core 3 implementing the primary winding 9 and
another flat rectangular wire conductor 2 to be directly wound in
an edge-wise winding form between the partition 11 and the outer
flange 8b on the magnetic core 3 implementing the secondary winding
10.
Accordingly, the outer flanges 8a and 8b can inhibit the edge-wise
winding form of the flat rectangular wire conductor 2 from being
loosened at the two lengthwise ends of the magnetic core 3 while
the partition flange 11 provided between the primary winding 9 and
the secondary winding 10 on the magnetic core 3 can definitely
separate and electrically insulate the two windings 9 and 10 from
each other thus improving the insulation as compared with that of
Embodiment 6. The magnetic core 3 may be arranged of an elliptical
shape in the cross section similar to that of Embodiment 2.
Embodiment 8
This embodiment is characterized by a magnetic core 3 having a
particular shape shown in FIGS. 15 and 16. The shape of the
magnetic core 3 comprises two halves separated at substantially the
center and each half becomes smaller in the diameter of the cross
section from each lengthwise end to an intermediate region. Flat
rectangular wire conductors 2 are wound in an edge-wise winding
form directly on the two halves of the magnetic core 3 thus
implementing the primary winding 9 and the secondary winding 10.
Similar to Embodiment 2, a recess 3c is provided in each length end
of the magnetic core 3.
Each half of the magnetic core 3 on which the primary winding 9 or
the secondary winding 10 is directly wound is sloped down from both
ends, the lengthwise end and the center of the magnetic core 3, to
the intermediate region. This allows the winding of the flat
rectangular wire conductor 2 to be securely wound along the
lengthwise direction without loosening outwardly at the two ends.
Also, the cross section at the center of the magnetic core 3
between the primary winding 9 and the secondary winding 10 is
greater than the halves on which the primary winding 9 and the
secondary winding 10 are directly wound, the two windings 9 and 10
can be separated and insulated from each other at a higher level of
certainty than in Embodiment 6. The magnetic core 3 may be arranged
of an elliptical shape in the cross section similar to that of
Embodiment 2.
Embodiment 9
An electromagnetic device of this embodiment is a two-winding
transformer having a primary winding and a secondary winding wound
directly on a substantially cylindrical, rod-like magnetic core 3
thereof, shown in FIGS. 17 and 18, with no use of an insulator such
as a coil bobbin. The magnetic core 3 is made of an Ni--Zn ferrite
material and arranged of substantially an elliptical shape, a
combination of a rectangular region and two semi-circular regions,
in the cross section shown in FIG. 19. In this embodiment, the
diameter of the semi-circular regions is about 6 mm while the
length of the rectangular region of the cross section is about 5
mm. The magnetic core 3 is about 30 mm in the length. Also, a
recess 3c having a diameter of about 2 mm and a depth of about 2 mm
is provided in each lengthwise end of the magnetic core 3.
The secondary winding 10 on the magnetic core 3 is fabricated by
providing 220 turns of a flat rectangular wire conductor 2 (e.g.
0.070 mm thick and 1.4 mm wide) directly in an edge-wise winding
form. It is found that the direct current resistance of the
secondary winding 10 is substantially 1.8 .OMEGA.. As shown in
FIGS. 17 and 18, the primary winding 9 is fabricated by providing 6
turns (3 turns shown in FIGS. 17 and 18) of a wire conductor (e.g.
0.2 mm in the wire conductor diameter and 0.51 mm in the overall
diameter) substantially between a low-voltage end 10a of the
secondary winding 10 and the lengthwise center of the magnetic core
3 over the secondary winding 10. The wire conductor may be an
insulated wire or magnet wire.
Because of the above described arrangement of this embodiment, the
primary winding 9 is wound over the secondary winding 10 thus
increasing the magnetic coupling between the two windings 9 and 10
and improving the efficiency of power transmission. As a result,
the electromagnetic device of this embodiment can produce a higher
secondary voltage as a pulse transformer than the previous
embodiment 7 or 8 where the two windings 9 and 10 are separately
wound on the magnetic core 3. For example, when the primary voltage
is 600 V, the pulsed output can be generated a peak value of 30 kV.
Also, as the primary winding 9 is located close to the low-voltage
end 10a of the secondary winding 10, it can be separated and
insulated by a marginal distance from the high-voltage end 10b of
the secondary winding 10. Moreover, since the primary winding 9 is
implemented by the coated wire conductor, the insulation between
the two windings 9 and 10 can be ensured. The primary winding 9 may
be provided adjacent to the low-voltage end 10a of the secondary
winding 10 along the lengthwise direction of the magnetic core 3
with equal success, as shown in FIG. 20.
Embodiment 10
An electromagnetic device of this embodiment is a two-winding
transformer having flat rectangular wire conductors 2a and 2b wound
in an edge-wise winding form directly on a substantially
cylindrical rod-like magnetic core 3 thereof with no use of an
insulator such as a coil bobbin to implement the primary winding 9
and the secondary winding 10 respectively shown in FIGS. 21 and 22.
The magnetic core 3 is substantially identical in the construction
to that of Embodiment 1 on which the flat rectangular wire
conductor 2b is directly wound in an edge-wise winding form
throughout the length thereof to develop the secondary winding 10.
Then, the primary winding 9 is fabricated by winding the flat
rectangular wire conductor 2a in an edge-wise winding from as
alternating several turns with the flat rectangular wire conductor
2b of the secondary winding 10 at a region close to the low-voltage
end 10a of the secondary winding 10 of the magnetic core 3.
As the primary winding 9 and the secondary winding 10 are
implemented by the edge-wise winding form of the flat rectangular
wire conductors 2a and 2b directly on the magnetic core 3, their
external dimensions are substantially equal to each other and can
thus contribute to the smaller or thinner size of the
electromagnetic device than that of Embodiment 9. Also, the flat
rectangular wire conductor 2a of the primary winding 9 like the
secondary winding 10 is directly wound on the magnetic core 3, the
two windings 9 and 10 can be fabricated in one single step thus
increasing the productivity.
Embodiment 11
This embodiment is characterized by a construction of the primary
winding 9 shown in FIGS. 23 and 24. The other arrangement is
substantially identical to that of Embodiment 9. The primary
winding 9 in this embodiment is fabricated by winding rectangular
foils of a wire conductor 12 and a rectangular sheet of an
insulating film 13 alternately on the secondary winding 10 which
has been fabricated by winding a flat rectangular wire conductor 2
in an edge-wise winding form directly on a magnetic core 3. The
conductor foil 12 has a pair of conductors 12a provided on both
ends of one side thereof which serve as the terminals of the
primary winding 9.
The process of fabricating the primary winding 9 is now explained
in more detail. As shown in FIG. 25, the wire conductor foil 12 is
placed on one end of the insulating film 13 of a rectangular sheet
and wound from the other end over the secondary winding 10 provided
directly on the magnetic core 3. More specifically, the insulating
film 13 is first wound on the secondary winding 10 and then, the
wire conductor foil 12 on the insulating film 13 is wound.
Accordingly, the conductor foil 12 is alternated with the
insulating film 13. As a result shown in FIG. 24, the wire
conductor foil 12 is wound in a multi-layer form via the insulating
film 13 on the secondary winding 10 to implement the primary
winding 9. This allows the insulating film 13 to insulate between
the primary winding 9 and the secondary winding 10 and
simultaneously between the layers of the wire conductor foil 12.
The primary winding 9 of this embodiment is provided between a
region close to the low-voltage end 10a of the secondary winding 10
and the lengthwise center of the magnetic core 3.
As its primary winding 9 is fabricated by winding the wire
conductor foil 12 and the insulating film 13, an electromagnetic
device of this embodiment can further be decreased in the
thickness. Also, as the distance between the primary winding 9 and
the secondary winding 10 is minimized, the magnetic coupling
between the same can be enhanced thus increasing the efficiency of
power transmission and thus producing a higher amplitude of the
output voltage. Moreover, as the primary winding 9 is increased in
the cross section of the wire conductor, its direct current
resistance can be reduced hence producing a greater level of the
primary current.
Embodiment 12
This embodiment is characterized by a construction of the primary
winding 9 shown in FIGS. 26 and 27. The other arrangement is
substantially identical to that of Embodiment 9. The primary
winding 9 is fabricated by winding a flat rectangular wire
conductor 2 in an edge-wise winding form on a magnetic core 3 to
develop the secondary winding 10, installing the magnetic core 3 in
a substantially cylindrical insulation casing 14 made of an
insulating material, and winding a wire on the insulation casing
14. The insulation casing 14 is sized not shorter than the overall
length of the magnetic core 3 to completely enclose the magnetic
core 3 and the secondary winding 10 therein. In particular, the
primary winding 9 incorporates several turns of the wire (for
example, a flat rectangular wire conductor) provided substantially
between the low-voltage end 10a of the secondary winding 10 and the
lengthwise center of the magnetic core 3.
Because of the above described arrangement of this embodiment, the
insulation casing 14 can definitely insulate between the primary
winding 9 and the secondary winding 10. Also, as the secondary
winding 10 is entirely enclosed in the insulation casing 14, its
marginal surface can be protected from dielectric breakdown
throughout the length from its high-voltage end 10b to the primary
winding 9.
Embodiment 13
This embodiment is characterized by a construction of the primary
winding 9 shown in FIG. 28. The other arrangement is substantially
identical to that of Embodiment 9. The primary winding 9 is
positioned by winding a fusible resin coated wire on the secondary
winding 10 and fusing between the coating of a flat rectangular
wire conductor 2 of the secondary winding 10 and the resin coated
wire of the primary winding 9.
As the two windings 9 and 10 are bonded to each other by fusion of
their coating to determine the position of the primary winding 9,
they can be inhibited from relatively dislocating from each other
thus eliminating any undesired variation in the properties. The
coating of the flat rectangular wire conductor 2 of the secondary
winding 10 provided in an edge-wise winding form may be made of a
fusible resin material and directly bonded by fusion to the
magnetic core 3 for positioning the secondary winding 10.
Embodiment 14
This embodiment is characterized by a construction of the primary
winding 9 shown in FIG. 29. A magnetic core 3 is provided with
leads 16 of thin metal strips fabricated by insertion forming,
arranged on which a flat rectangular wire conductor 2 is wound in
an edge-wise winding from to develop the secondary winding 10, and
installed in the interior 15a of a synthetic resin casing 15. Each
pair of the leads 16 provided on both sides of the magnetic core 3
are bridged at their distal end by a thin metal lead strip 17. As
the lead strip 17 is joined at both ends to the distal ends of the
paired leads 16, they extend about the secondary winding 10 as
serving as the primary winding 9 (its two turns only shown in the
drawing). This arrangement can contribute to the smaller size or
the lower dimension of the electromagnetic device (a transformer)
of this embodiment.
Embodiment 15
In Embodiment 9, the primary winding 9 is implemented by the coated
wire of which the overall diameter is set to substantially five
times greater than the diameter of its wire conductor because of a
point of view that a dielectric breakdown between the primary
winding 9 and the secondary winding 10 possibly occurs at the
marginal surface close to the high-voltage end 10b of the secondary
winding 10. However, when the coated wire of such a greater
diameter is used, a resultant electromagnetic device (a
transformer) becomes greater in dimensions thus interrupting the
reduction of the overall size. Also, as the coated wire is round in
the cross section, it may hardly be positioned on the secondary
winding 10 and, if worse, may be wound to a greater thickness.
While the diameter of the wire of the primary winding 9 in
Embodiment 12 is successfully decreased, the overall dimensions of
the electromagnetic device (transformer) become greater due to the
size of the insulation casing 14 and may be increased in the number
of components or assembled with much difficulty.
This embodiment is an electromagnetic device (a transformer)
comprising a primary winding assembly 18 including the primary
winding 9 with insulators and a magnetic core 3 having a flat
rectangular wire conductor 2 wound in an edge-wise winding form
thereon and coupled to the primary winding assembly 18, as shown in
FIGS. 30 and 31. While this embodiment is characterized by the
installation of the primary winding 9, its other arrangement is
identical to that of Embodiment 9.
The primary winding assembly 18 includes a substantially
cylindrical housing 19 of an insulating resin material (a first
insulating material) arranged of an elliptical shape in the cross
section as shown in FIG. 32. The housing 19 is made of a
thermoplastic resin material such as poly-ether-imide and has
several turns of a groove 19a provided circumferentially in the
outer surface thereof for holding the primary winding. Also, the
housing 19 has a couple of lengthwisely extending projections 19c
provided thereon, each projection having a groove 19b provided
thereon for accepting each end of the primary winding.
When an electrically conductive resin 21 which is highly flowable
is poured into the groove 19a of the housing 19 installed in a set
of molds 20 shown in FIG. 33, it easily runs from the groove 19a to
the grooves 19b. As its resin 21 is completely cured, the primary
winding 9 is shaped extending along the grooves 19a and 19b on the
outer surface of the housing 19.
As the housing 19 with the primary winding 9 is entirely covered
with a synthetic resin (a secondary insulating material, e.g.
poly-ether-imide identical to the material of the housing 19) but
its two lengthwise end openings remaining open, the primary winding
assembly 18 containing the housing 19 covered with the secondary
insulating material of a shape 22 is completed.
Finally, as the magnetic core 3 with the secondary winding 10 is
installed in the housing 19 of the primary winding assembly 18 and
the primary winding 9 is connected at both ends to terminal strips
23, the electromagnetic device (a transformer) of this embodiment
is completed (See FIGS. 30 and 31). The primary winding assembly 18
is arranged extending substantially between the low-voltage end 10a
of the secondary winding 10 and the lengthwise center of the
magnetic core 3.
Because of the above arrangement of this embodiment, the insulation
between the primary winding 9 and the secondary winding 10 can be
implemented by the primary winding assembly 18. Since the secondary
insulating material of the shape 22 encloses the housing 19 on
which the primary winding 9 has been developed with the
electrically conductive resin material 21, it can favorably
insulate the primary winding 9 from the high-voltage end of the
secondary winding 10. Also, as the primary winding 9 is fabricated
by filling the grooves 19a and 19b of the housing 19 with the
highly flowable electrically conductive resin material 21 with no
need of the conventional step for winding a wire to develop the
primary winding 91 its assembling process can be facilitated thus
improving the overall productivity. As its dimensional properties
remain free from unwanted variations which are pertinent to the
coated wire and its winding exhibits a minimum of winding faults,
the primary winding 9 can be small or thin. As a result, the
electromagnetic device can hence be minimized in the overall size
or thickness.
While the magnetic cores 3 of this embodiment and the previous
embodiments 1 to 14 are made of a bar-like ferrite material and
polished at the surface, they may not be polished but remain rough.
In the latter case, the surface roughness or mathematical average
roughness (Ra) of the magnetic core 3 can preferably be 0.8 .mu.m
or greater. This eliminates the step of polishing the magnetic core
3 and can hence reduce the production cost of the magnetic core 3.
In case that the surface roughness of the magnetic core 3 is
declined, it may cause the flat rectangular wire conductor 2 to be
slipped down and fractured during the edge-wise winding as shown in
FIG. 35. When the magnetic core 3 remains rough at the surface, it
can inhibit the flat rectangular wire conductor 2 from being
fractured thus permitting ease of the edge-wise winding.
Embodiment 16
Prior to the description of this embodiment, a circuitry
arrangement in the conventional high-voltage generating device will
be explained referring to FIG. 38. The conventional device acts as
an igniter for supplying a high intensity discharge lamp Lp with a
pulsed high voltage and comprises a pair of input ports T1 and T2
for receiving the high voltage, a pair of output ports T3 and T4
connected to the high intensity discharge lamp Lp, a pulse
transformer PT of which the secondary winding is connected between
the input port T1 and the output port T3 at the high voltage side
and the primary winding is connected between the two input ports T1
and T2, a switching element SW connected between the low voltage
side of the primary winding of the pulse transformer PT and the
input port T2 at the lower voltage side, a resistor R1 connected
between the input port T1 at the high voltage side and the high
voltage side of the primary winding of the pulse transformer PT,
and a capacitor C1 connected in parallel with both the primary
winding of the pulse transformer PT and the switching element SW.
In action of the conventional device, a voltage input received by
the two inputs T1 and T2 while the high intensity discharge lamp Lp
is not lighted is passed via the resistor R1 to the capacitor C1
which is thus charged. When the voltage at both ends of the
capacitor C1 is increased to a given level, it turns the switching
element SW on. This allows the power to be discharged from the
capacitor C1 and transmitted via the switching element SW to the
primary winding of the pulse transformer PT which then generates a
pulsed high voltage at its secondary winding. The pulsed high
voltage is then received by the high intensity discharge lamp Lp
which in turn creates dielectric breakdown.
FIG. 39 illustrates an exemplary waveform of the pulsed high
voltage output of the conventional device where a high frequency
component is superimposed on the waveform of a resonant voltage
generated by the action of the capacitor C1 at the primary winding
of the pulse transformer PT and boosted by the pulse transformer
PT. This may result from the effect of any parasitic capacitance
since the pulse transformer PT is not of an ideal form. It is
however essential for allowing the high intensity discharge lamp Lp
to start a dielectric breakdown promptly that the waveform of the
pulsed high voltage is as close to its fundamental form as possible
without the effect of the high frequency component. Also, when the
voltage output of the conventional device is rapidly settled down
to zero in the amplitude, its stressing effect on the components
including the capacitor C1 can be minimized. As a result, the
components of the circuitry arrangement to be employed can be eased
in the resistance to high voltage and thus reduced in both the size
and the price.
The high-voltage generating device of this embodiment has a couple
of metal strips 24 provided adjacent to both ends of the magnetic
core 3 in a pulse transformer PT as shown in FIG. 36, thus
minimizing the oscillation of the high frequency component. More
specifically, the magnetic core 3 is magnetically open at both
ends. When the magnetic flux leaked from the two ends of the
magnetic core 3 and passed across the metal strips 24 is varied by
the effect of the high frequency oscillation, it generates an eddy
current on the metal strips 24. As a result, the eddy current loss
will occur and offset the high frequency oscillation. The pulse
transformer PT in this embodiment is implemented by the
electromagnetic device (a transformer) of any of Embodiments 6 to
15.
As described, the high voltage waveform supplied to the high
intensity discharge lamp Lp can be corrected to close to the
fundamental form shown in FIG. 37 with its high frequency component
successfully offset by the eddy current loss created on the metal
strips 24. Also, as the oscillation of the voltage output is
rapidly reduced to zero, its stressing effect on the components
including the capacitor C1 can be minimized. This allows the
components to be used which are eased in the resistance to high
voltage and thus decreased in both the size and the price. The
metal strips 24 may be replaced by leads which are provided for
electrically connecting between the components and located adjacent
to both ends of the magnetic core 3 of the pulse transformer PT. As
a result, the components to be used can be reduced in the total
number and their arrangement can be simplified.
Embodiment 17
This embodiment is characterized by a high-voltage generating
device where the primary winding of a pulse transformer PT is
connected in parallel with a resistor Ra as shown in FIG. 40. The
other arrangement is substantially identical to that of the
conventional device shown in FIG. 38. The high frequency
oscillation can thus be offset by the loss created in the resistor
Ra which is connected in parallel with the primary winding. For
providing the same effect, the primary winding of the pulse
transformer PT may be connected in series with a resistor Rb as
shown in FIG. 41.
Embodiment 18
This embodiment is characterized by a high-voltage generating
device where a high intensity discharge lamp Lp is provided
integral with a socket which is arranged detachable as shown in
FIG. 42. The high-voltage generating device of this embodiment
comprises a main assembly 30 made of a synthetic resin material and
a shield cover 50 covering the back and lateral sides, but not the
front side, of the main assembly 30 as best shown in FIG. 43. The
main assembly 30 includes a body 31 containing major components
including the pulse transformer PT described with Embodiment 16, a
cover 32 covering the front side of the body 31, and a lid 33
closing the rear side of the body 31.
The cover 32 has a socket opening 34 of substantially a round shape
provided in the front side thereof and a group of bayonet stoppers
35 provided on the circumferential edge about the socket opening
thereof. The stoppers 35 are formed integral with the
circumferential edge about the socket opening 34 and provided in
the form of notches opening towards the center. More particularly,
the stopper 35 is an L shaped recess comprising a vertical groove
35a for accepting each engaging tab (not shown) provided on the
outer surface of a base of the high intensity discharge lamp Lp
which is inserted from the front to the back in the socket opening
34 and a horizontal groove 35b continuously communicated with the
vertical groove 35a. In addition, the stopper 35 has a stopper
recess 35c provided in the innermost thereof for holding the
engaging tab at the engaging position.
The body 31 includes a substantially cylindrical tube 36
accommodated in the socket opening 34 of the cover 32 and an
engaging projections 38 provided thereon for engaging with engaging
slots 37 provided in the lateral side of the cover 32. As the cover
32 is placed over the front side of the body 31, its engaging
projections 38 come into engagement with the corresponding engaging
slots 37. As a result, the body 31 and the cover 32 are joined
together with its tube 36 accommodated in the socket opening 34
(See FIG. 42). The body 31 also has a center tube 39 of
substantially a cylindrical shape provided upright in the center of
the tube 36 and a center electrode 40 provided in the center tube
39 for direct contact with a center electrode (not shown) of the
discharge lamp base. Also, a group of outer electrodes 41 are
provided on the tube 36 for direct contact with corresponding outer
electrodes (not shown) mounted on the outer side of the lamp base.
When the body 31 and the cover 32 are joined together, contacts 41a
of the outer electrodes 41 of its tube 36 come to face the inner
side about the socket opening 34 of the cover 32. More
particularly, when the lamp base is inserted into the socket
opening 34 of the cover 32, its engaging tabs move into the
vertical grooves 35a of the stoppers 35. As the lamp base is
twisted, its engaging tabs move into the horizontal grooves 35b and
finally come in direct engagement with the corresponding stopper
recesses 35c. Simultaneously, the center electrode of the lamp base
is inserted into the center tube 39 to come into direct contact
with the center electrode 40. Also, the outer electrodes of the
lamp base come into direct contact with the corresponding contacts
41a of the outer electrodes 41 about the socket opening 34 of the
tube 36. As a result, the high intensity discharge lamp Lp is
coupled to the high-voltage generating device of this embodiment
electrically and mechanically.
The body 31 also has a first component recess 42 provided in the
front side thereof for accommodating the circuitry components
including a resistor R1 and a capacitor C1. As best shown in FIG.
44, the body 31 has a transformer recess 43 provided in the back
side thereof for accommodating a pulse transformer PT. The pulse
transformer PT is identical in the construction to the
electromagnetic device (a transformer) of Embodiment 9, having a
flat rectangular wire conductor 2 wound in edge-wise winding form
on a rod-like magnetic core 3 of substantially a cylindrical shape
in the cross section to implement the secondary winding 10 and
substantially six turns of a wire provided on the secondary winding
10 to implement the primary winding 9, as shown in FIG. 45.
The lid 33 has a group of engaging slots 45 provided in a
circumferential wall 33a thereof for engagement with corresponding
engaging projections 44 provided on the outer surface of the body
31. When the lid 33 is placed over the back side of the body 31,
its engaging slots 45 come to accept the corresponding engaging
projections 44. As the body 31 is coupled with the lid 33, it can
be closed up at the back side with the lid 33.
The shield cover 50 is a box shape of an electrically conductive
magnetic material having one side opened. The shield cover 50 has a
fitting slot 47 provided in a circumferential wall thereof for
engagement with a fitting projection 46 provided on the outer side
of the cover 32. When the main assembly 30 consisting mainly of the
body 31, the cover 32, and the lid 33 is inserted from the back
into the shield cover 50, the fitting projection 46 of its cover 32
comes in engagement with the fitting slot 47 thus coupling the main
assembly 30 with the shield cover 50.
As the pulse transformer PT in the main assembly 30 is accommodated
in the body 31 with its magnetic core 3 facing at both ends the
inner side of the shield cover 50, its magnetic core 3 of the main
assembly 30 when coupled to the shield cover 50 develops a closed
magnetic circuit together with the shield cover 50. Because the
main assembly 30 is protected with the shield cover 50 and its
pulse transformer PT allows the magnetic core 3 to develop the
closed magnetic circuit together with the shield cover 50, any
noise generated and emitted from the high-voltage generating device
can favorably be attenuated and simultaneously the (high voltage)
output of the pulse transformer PT can be increased. Also, the
device itself can be minimized in the overall size or thickness.
The shield cover 50 of this embodiment also acts as the metal
strips 24 of Embodiment 16. As the metal strips 24 are not needed,
the components can thus be decreased in the total number and their
arrangement can be simplified.
Embodiment 19
FIG. 46 is a construction view of an electromagnetic device of this
embodiment and FIG. 47 is an explanatory cross sectional view
showing the shape of a recess provided in the magnetic core 3 shown
in FIG. 46. The electromagnetic device shown in FIG. 46 comprises
the rod-like magnetic core 3 having an intrinsic resistance of not
smaller than 10.sup.3 .OMEGA.m, a coil winding 2 provided on the
magnetic core 3 by winding a flat rectangular wire in an edge-wise
winding form with no use of a bobbin as the insulator, a coil
winding 1 of an insulator coated wire (acting as the primary
winding 9) provided directly over the coil winding 2, a resin
casing 5 arranged for accommodating those components, and a group
of terminals 6 extending outwardly from the casing 5 and connected
to the coil windings.
As the coil windings 1 and 2 are provided directly on the magnetic
core 3 with no use of the bobbin, the terminals 6 of this
embodiment are joined with non of the bobbin. This embodiment
allows the terminals 6 to be connected together by a hoop material
60 as shown in FIG. 46c. As apparent, the terminals 6 joined to the
hoop material 60 are connected to the corresponding coil windings.
Since the terminals 6 are drawn out in one direction as shown in
FIG. 46a, the hoop material 60 can be arranged of a simpler shape.
Even if the casing 5 is made by filling or molding of a resin
material for giving the electrical insulation as shown in FIG. 46b,
the terminals 6 are aligned in a row and they can thus be joined to
the corresponding coil windings with much ease at the succeeding
step.
Embodiment 20
Referring to FIG. 47, this embodiment allows a magnetic core 3 to
have a recess 3c provided in each end thereof defining a bottom
3c2. The recess 3c is arranged to have a tapered shape which
becomes smaller in the diameter from an opening 3c1 to the bottom
3c2. In production, the magnetic core 3 is supported by not a rod
jig shown in FIG. 70 but a rod K having a tapered projection K1. As
the magnetic core 3 is removed and tilted down about the corner
point P1 of the rod K, its bottom edge portion about the opening
3c1 of the recess 3c can successfully clear the projection K1 of
the rod K where the radius of the movement of the edge portion P2
at the recess 3c of the magnetic core 3 about the point P1 is
slightly greater than the distance from the projection point P3 of
the edge of the projection K1 to the corner point P1 of the rod K.
This inhibits any undesired tipping off at the edge about the
recess 3c of the bottom of the magnetic core 3.
Embodiment 21
FIG. 48a illustrates the magnetic core of an electromagnetic device
of this embodiment. The magnetic core 3A of the electromagnetic
device has a recess 3c provided in each end thereof which is
identical to that of the previous embodiment and is arranged of an
elliptical shape in the cross section. The other arrangement is
identical to that of the previous embodiment. As its magnetic core
3A is rather flat in the shape, the electromagnetic device can be
implemented as a thin transformer. Also, the recess 3c has a
tapered shape as described. As the magnetic core 3A is elliptical
in the cross section, it may hardly be tilted down in a direction
denoted by the arrow shown in FIG. 48b but easily fallen in another
direction denoted by the arrow shown in FIG. 48c. It is hence
understood that the tapered effect may be provided in the recess 3c
only along the direction orthogonal to the lengthwise direction of
the magnetic core 3A for inhibiting any undesired tipping off.
Embodiment 22
FIG. 49 illustrates an electromagnetic device of this embodiment
having a magnet core and a group of coil windings. The
electromagnetic device is differentiated from that of Embodiment 19
by the fact that the coil winding 1 wound on the coil winding 2 has
two leads 1L and 1R thereof drawn out specifically. Assuming that
the coil winding 1 acts as the primary winding and the coil winding
2 acts as the secondary winding, the coil winding 2 is fabricated
by winding a flat rectangular wire of foil shape, which is high in
the engaging rate, in an edge-wise winding form on the magnetic
core 3. Accordingly, the coil winding 2 can be increased in the
number of turns without decreasing the cross sectional size. The
electromagnetic device is hence used as a small sized, high-voltage
transformer which can easily produce a high voltage of, for
example, several to tens kilovolts across its secondary winding 2
when the coil winding 1 is loaded as the primary winding with a
voltage of hundreds bolts to a few kilovolts. In that case, the
magnetic circuit of the coil windings 1 and 2 is an open circuit
coaxial with the magnetic core 3.
It is known that the open circuit allows the coupling between the
primary and secondary windings to be more increased when the coil
winding 1 is located as the primary winding on the center of the
magnetic core 3 than on either end of the same. The coil winding 1
shown in FIG. 46 is biased towards the center of the coil winding 2
and more particularly located leftwardly of the center of the coil
winding 2 of which the right lead 2R acts as a high-voltage end.
The location of the coil winding 1 leftwardly of the center of the
coil winding 2 is based on the following reason. As shown in FIG.
46a, the potential between 2R and 1L(1R) is as high as several to
tens kilovolts while the potential between 2L and 1L(1R) ranges
from hundreds volts to a few kilovolts. Also, as the joint between
the lead of each coil winding and the terminal 6 is implemented by
an uncovered metal joint, it may trigger dielectric breakdown when
a gap is generated between the resin material housing and the
high-voltage transformer. For inhibiting any dielectric breakdown,
the distance between 2R and 1L(1R) is enlarged.
When the coil winding 1 is located on the lead 2L of the coil
winding 2, the protection from dielectric breakdown can be enhanced
but the coupling between the primary and secondary windings will be
declined thus lowering the level of the high-voltage output at the
secondary winding. For compensation, the coil winding 1 of this
embodiment is slightly biased towards the center of the coil
winding 2 to guarantee the coupling between the primary and
secondary windings as shown in FIG. 49 while its two leads 1L and
1R are biased towards the low-voltage end 2L of the coil winding 2.
This allows the high-voltage transformer to be improved in the
resistance to dielectric breakdown while ensuring the coupling
between the primary and secondary windings.
Embodiment 23
FIG. 50 illustrates an electromagnetic device of this embodiment
having a magnetic core, a group of coil windings, and an insertion
molded member. The electromagnetic device is differentiated from
the previous one by the fact that the casing 5 is replaced by an
insertion molded member 5A for drawing the leads of the coil
windings 1 and 2. As its magnetic core 3A has an elliptical shape
in the cross section as shown in FIG. 50a, the electromagnetic
device of this embodiment can be used as a thin transformer.
While the leads 1L and 1R of the coil winding 1 as the primary
winding are drawn out from a location close to the low-voltage end
2L of the coil winding 2 in the previous embodiment, the lead 1R of
the coil winding 1 of this embodiment close to the high-voltage end
2R of the coil winding 2 only is biased towards one particular end
of the magnetic core 3A where the low-voltage end 2L of the coil
winding 2 is located. This arrangement will also improve the
insulation function. More particularly, the two leads of the coil
winding 2 are drawn out along the thin side of the magnetic core
3A. This allows the insertion molded member 5A to remain minimum in
the thickness as shown in FIG. 50b. Also, the two leads 2L and 2R
of the coil winding 2 are located diagonal to each other so as to
be distanced maximum from each other.
As shown in FIG. 50b, the insertion molded member 5A has a set of
grooves 51A provided circumferentially in the outer sides thereof
between the high-voltage end 2R and the other end 2L (1L and 1R).
As the grooves 51A extend throughout the outer sides of the
insertion molded member 5A to form a series of peaks and valleys on
the surfaces. Accordingly, the surface (interface) distance between
the high-voltage end 2R and the other end 2L (1L and 1R) on the
insertion molded member 5A can be elongated. As a result, the
insulation function between the one end 2R and the other end 2L (1L
and 1R) can be improved thus allowing the small sized transformer
to be easily fabricated having a higher level of the
insulation.
Embodiment 24
FIG. 51 illustrates an electromagnetic device of this embodiment
having a magnetic core, a group of coil windings, and an insertion
molded member. The electromagnetic device is similar to that of the
previous embodiment, except that the insulation coated coil winding
1 is replaced by a coil winding 1A of a single wire with a bobbin
40 having a pair of terminals 41 and serving as the insulation
coating, the coil winding 1A wrapped up at both ends with the
paired terminals 41 of the bobbin 40. In this arrangement, while
the bobbin 40 can increase the insulation function between the
primary winding and the secondary winding, the connection between
its paired terminals 41 and the coil winding 1A can be facilitated.
The coil winding 1A is fabricated by the single wire of a low
price, not the high-voltage insulation coated wire which is
relatively high in the cost, thus contributing to the low price of
a resultant high-voltage transformer.
Embodiment 25
FIG. 52 is a schematic view of an electromagnetic device of this
embodiment at a step of its production. FIG. 53 is a plan view of
the electromagnetic device shown in FIG. 52, FIG. 54 is a
perspective view of a magnetic core and coil windings used in the
electromagnetic device shown in FIG. 52, FIG. 55 is a schematic
view of the electromagnetic device at a production step prior to
the step of FIG. 52, and FIG. 56 is a plan view of the
electromagnetic device shown in FIG. 55. The process of fabricating
the electromagnetic device prior to the steps of FIGS. 52 and 53.
As shown in FIG. 54, the coil windings 1 and 2 are provided on the
magnetic core 3A of an elliptical shape in the cross section with
no use of an insulator to develop a first intermediate product.
More specifically, the coil winding 2 is fabricated by winding a
flat rectangular wire in an edge-wise winding form on the outer
side of the magnetic core 3A and then the coil winding 1 is
provided on a predetermined location of the coil winding 2.
This is followed, as shown in FIGS. 55 and 56, by connecting ends
of the coil windings 1 and 2 of the first intermediate product to
corresponding terminals 6 of a lead frame 60A made of a single
metallic strip to develop a second intermediate product. The second
intermediate product is then placed in a set of unshown molds which
are in turn filled with a thermoset resin material such as
unsaturated polyester (by injection molding). As a result, a third
intermediate product is given having the lead frame 60A joined with
an insertion molded member 5B as shown in FIGS. 52 and 53. The
above injection molding process can reduce the conventional vacuum
filling process, which takes four or more hours, to as short as two
minutes. Also, as the electromagnetic device employs a case-less
arrangement, its overall dimensions can significantly be
decreased.
Embodiment 26
FIG. 57 illustrates a perspective view and a partially cross
sectional view of an electromagnetic device of this embodiment.
FIG. 58 is a plan view of the electromagnetic device shown in FIG.
57 and FIG. 59 is an explanatory view showing steps of shifting the
electromagnetic device from an intermediate form to a finished form
shown in FIG. 58. Particularly in this embodiment, the third
intermediate product of the previous embodiment is provided with
the coil windings 1 and 2 connected at their ends to corresponding
terminals 6 of the lead frame 60A and then, the redundancy of the
lead frame 60A is removed off for electrical isolation from the
ends of the coil windings 1 and 2. As a result, a fourth
intermediate product shown in FIG. 59a is given. Then, the
terminals 6 are folded down in their respective directions (for a
desired pattern) as shown in FIG. 5b, completing the
electromagnetic device of this embodiment shown in FIGS. 57 and
58.
As shown in FIG. 57a, there are a group of grooves 51B provided
between the terminal 6 (2R) and the other terminals 6 (1L, 1R) in
one side of the insertion molded member 5B, the terminal 6 (2R)
connected with the high-voltage end 2R of the coil winding 2 and
the terminals 6 (1L, 1R) connected with the two ends 1L and 1R of
the coil winding 1. As the insertion molded member 5B has a series
of peaks and valleys on the surface, its surface distance is
between the two ends thus improving the insulation function and
inhibiting any current leakage. The grooves 51B are of no
limitations and may be replaced by a row of projections. Denoted by
50B in FIG. 57b is a filling material of the insertion molded
member 5B. The electromagnetic device of this embodiment fabricated
by the above manner is preferably used in a discharge lamp igniter
which supplies a discharge lamp La as the headlight of vehicle with
power and holds it at its lighting condition as shown in FIG. 60.
The discharge lamp igniter includes a starter (igniter) circuit IG
for feeding the discharge lamp La with a pulsed high voltage for
illumination, as shown in FIG. 61. The igniter circuit IG is driven
by an inverter INV. The electromagnetic device is installed at a
region R2 in the igniter circuit IG denoted by the dotted line in
FIG. 61 and its insertion molded member 5B made of a thermoset
resin material is also protected with an enclosure of thermoplastic
resin material (to form a double insulation). The electromagnetic
device with its terminals 6 exposed to the outside is covered with
the thermoplastic resin enclosure. Because of the double
insulation, the electromagnetic device is almost thoroughly
protected by the thermoplastic resin except its terminals and can
thus be improved in the insulation distance and the moisture-proof
function. Also, the grooves 51B extending from one end to the other
end of one side of the insertion molded member 5B can serve as
passages for positively distributing flows of the thermoplastic
resin material during the molding process, hence promoting the
flowability of the thermoplastic resin material in molten form.
Embodiment 27
FIG. 62 illustrates an electromagnetic device of this embodiment
having a magnetic core and a group of coil windings. The
electromagnetic device is modified in which the coil winding 1 of
an insulation coated wire is replaced by a fusible coil winding 1B.
The process of fabrication starts with winding a flat rectangular
wire in an edge-wise winding form on the outer surface of the
magnetic core 3 to develop the coil winding 2. Then, an UV curable
adhesive is applied to two regions R3 and R4 and cured by
irradiation of UV light. This is followed by winding a fusible wire
on a predetermined region of the coil winding 2 to develop the coil
winding 1B and energizing and fusing the coil winding 1B for
bonding with the coil winding 2. As understood, the process can
easily be carried out. Also, as its two ends are bonded by the
adhesive to the side of the magnetic core 3, the coil winding 2 can
hardly be detached by its spring-back effect.
Embodiment 28
FIG. 63 illustrates an electromagnetic device of this embodiment
having a magnetic core and a coil winding. The electromagnetic
device is substantially identical in the construction to that of
Embodiment 1 except that the coil winding 2 excluding its two ends
is almost entirely covered with a thin coating C. When the magnetic
core 3 is decreased in the diameter for downsizing, the coil
winding 2 provided in an edge-wise winding form on the magnetic
core 3 becomes smaller in the curvature radius and its coating may
easily be torn off thus causing short-circuit between two adjacent
turns of the coil winding 2. In this embodiment, after provided in
an edge-wise winding form on the magnetic core 3, the coil winding
2 is protected with the thin coating C. This can inhibit unwanted
short-circuit between any two turns of the coil winding 2.
Embodiment 29
FIG. 64a illustrates an electromagnetic device of this embodiment
having welding joiners 70. The welding joiner 70 is joined to one
end of an insulation coated wire 8 of the primary winding and used
as a terminal 6 of the electromagnetic device. The welding joiner
70 is arranged of a foldable shape comprising a flat base portion
71 extending in one direction, a folded portion 72 extending from
one side at a right angle to the one direction, and an extending
portion 73 allowing the folded portion 72 to face the flat portion
71. Also, a tab-like portion is provided extending from the other
side than the folded portion 72 side of the base portion 71 and
bent upwardly, thus acting as a positional error inhibitor 74. The
length of the positional error inhibitor portion 74 from the flat
portion 71 is equal or slightly greater than the diameter of the
insulation coated wire 8. Particularly, the positional error
inhibitor portion 74 is located as spaced from the folded portion
72.
The welding joiner 70 is securely coupled to the insulation coated
wire 8 when pressed and welded between welding electrodes 78 as
shown in FIG. 64b, thus holding but not detaching from the
insulation coated wire 8 and giving the joint of improved stability
and durability. Also, as its length from the base portion 71 is
equal or slightly greater than the diameter of the insulation
coated wire 8, the positional error inhibitor portion 74 of the
welding joiner 70 can certainly inhibit any further dislocation of
the insulation coated wire 8. Accordingly, no detachment of the
insulation coated wire 8 from the welding joiner 70 will be
allowed. Moreover, as the positional error inhibitor portion 74 is
spaced by a distance from the folded portion 72, any short-circuit
between the positional error inhibitor portion 74 and the folded
portion 72 will be disallowed. This allows the extending portion 73
to emit a degree of Joule heat generated by the application of
welding energy and transferred from the folded portion 72 thus
fusing and removing the insulation coating of the coated wire
8.
INDUSTRIAL UTILIZATION
As set forth above, the electromagnetic device, the high-voltage
generating device, and the method for fabricating the
electromagnetic device according to the present invention are
favorably applicable to and can contribute to the reduction of the
size or thickness of a pulse transformer also called an igniter for
starting a common high intensity discharge lamp.
* * * * *